Various ultrathin oxynitride gate dielectrics of similar thickness (similar to 1.4 nm) processed by a rapid thermal NO-nitrided oxide (RTNO), a remote plasma nitrided oxide (RPN), a remote plasma nitridation of N2O oxide with rapid thermal NO annealing (N2O + RPN + NO), and a rapid thermal reoxidation of remote plasma nitrided oxide (ReoxRPN) are reported for the first time as a means to extend the reliability scaling limit of SiO2/oxynitride-based gate dielectrics. The N2O + RPN + NO gate dielectric films show superior interface properties, significantly reduced leakage current, and improved reliability compared to other gate dielectrics fabricated by different processes. (c) 2005 The Electrochemical Society.